We're getting ever closer to the biggest race in the triathlon calendar, which began in 1978 with 15 hardy souls and now attracts the pinnacle of long-distance athletes from all over the world.

From ITU and Olympic champions to previous Ironman World Championship winners, there are a host of contenders to take the title in 2015, including Brits Tim Don and Joe Skipper, with the potential there for a fiercely-fought battle akin to Scott and Allen in 1989 and McCormack and Raelert in 2010.

10. Matt Hanson

There can’t be many professionals in Kona newer to the sport than Hanson, who only took up triathlon in 2011, but as a professor of exercise science and director of the human performance program at Buena Vista University, he's well placed to optimise his training and the rise has been impressive.

Two years ago he finished a mere ninth in his age-group (25-29) in Hawaii, but hinted at his potential with a 2:53 marathon, the fastest amateur split. Since turning professional he has won Ironman Chattanooga in a course record 8:12:32 last year and did the same this time around in Texas with 8:07:43 where he ran down a 9min deficit to Joe Skipper and extended to a 9min margin of victory. That 2:45:47 showing was not even Hanson’s fastest marathon in an Ironman - the 30-year-old ran a 2:41:38 on the same course last year and a 2:42:07 in Coeur d’Alene, both course records.

The likelihood is that Hanson will struggle in the swim and suffer on the bike, but with few expectations, the man from Concord, Massachusetts, might just fly on the run.

9. Tim Don

Don validated his full distance race requirement by winning with a comfortable 4min cushion on debut in Mallorca last September, with his qualification chances already buffered by a glut of points from last year’s third place at the Ironman World 70.3 Championship.

The Boulder-based Londoner wisely elected not to fit in another full distance effort, and instead took to the 70.3 circuit with victories in Monterrey, Brasilia, Utah and Ecuador; a predominantly South American schedule linked to a Coca-Cola team endorsement signed alongside British female professional Rachel Joyce.

It was all going so well until Don came off his bike just before the business-end of the season. Thirty-six stitches in his face, two in his knee, six internal and two to save his thumb meant he flew to Austria for the 70.3 worlds topped up on antibiotics, and pulled out before the end.

Missing the last big training block is far from perfect preparation for a first crack at Kona, but enforced layoffs can be turned to a positive, and Don is of that mindset, with assurances he’s fit and firing if a little fatigued. In some ways it’s exactly where you should be a few weeks out, and he does have a lifetime of endurance conditioning to fall back on.

8. Joe Skipper

Past results: Second place IM Texas 2015; three podiums at IM UK

This could be the highest achieving year yet for British male triathletes in Kona, with debut appearances from Tim Don and David McNamee. Skipper, though, could top the lot. Unlike the others, the 27-year-old from Norfolk has not come through the British Triathlon system but since stepping up to long course action has been a breath of fresh air, with his honest endeavour, candid views, heavy-hitting bike legs and slick run splits.

He’s had three consecutive podium finishes at Ironman UK, a race he's desperate to win and must surely land within a couple of years. But the result that really put his name forward as a contender – and into exalted company in the saddle – was a runner-up spot in the Ironman North American Championship in Texas. A 4:10:07 bike split was the fourth fastest official Ironman bike ride ever. Given the company he’s keeping, the reality is Skipper is only a dark horse for the top 10, but his strong bike leg could make him an exciting prospect.